Compact, high power, high voltage, long-distance electrical transmission line structure

Abstract

Embodiments generally relate to long-distance, 3-phase, AC electricity transmission structures. In one embodiment, the structure comprises an array of beams, the array comprising a sub-array of 3N active beams, wherein N is an integer, one passive beam on the right side of the sub-array of active beams; and one passive beam on the left side of the sub-array of active beams. The centers of the cross-section of each of the active and passive beams lie in a single plane. In another embodiment, the structure comprises an array of 3N metal active beams, wherein N is an integer; and a tunnel of rectangular cross-section with either 90 degree or rounded corners. The array of beams is mounted within the tunnel, and the two side walls of the tunnel are lined with a highly conductive metal having a thickness similar to the thickness of metal used in the active beams.

The invention claimed is: 
     
       1. A long-distance, 3-phase, AC electricity transmission structure, comprising: an array of beams for carrying 3-phase AC electricity, the array comprising: a sub-array of 3N active beams, wherein N is an integer; a first passive beam, grounded at both ends, on the right side of the sub-array of active beams; and a second passive beam, grounded at both ends, on the left side of the sub-array of active beams; wherein the centers of the cross-section of each of the active and passive beams lie in a single line and in a single plane, the single plane including the longitudinal axis of the array; wherein each of the active beams has the same electrical transmission impedance as any other of the active beams; and wherein each beam of the array comprises segments welded together at a slight angle, so that each beam meanders to the right and left when viewed from above along the length of the array, along axes orthogonal to the longitudinal axis of the array. 
     
     
       2. The structure of  claim 1 , additionally comprising:
 an electrically insulating gas or mixture of gases in the space between the beams of the array; 
 a tunnel of rectangular cross-section with either 90 degree or rounded corners, the tunnel comprising two side walls, a ceiling that connects directly to the side walls, and a floor that connects directly to the side walls, at least one of the ceiling, the side walls, and the floor of the tunnel comprising a material that is a poor electrical conductor, wherein the array of beams is mounted within the tunnel and wherein no part of any beam directly contacts the side walls, ceiling or floor; and 
 a plurality of insulating structures supporting the beams of the array either from the floor of the tunnel or from the ceiling of the tunnel or both, the insulating structures corresponding to each beam being located at periodically spaced locations along the length of the corresponding beam. 
 
     
     
       3. The structure of  claim 2 , wherein the tunnel is sealed such that the array of beams is protected from weather, such as rain, lightning, fog or snow, and from water incursion. 
     
     
       4. The structure of  claim 3 , wherein the ceiling, the walls, and the floor of the tunnel comprise one or more materials having carefully controlled thermal conductivity, such that the heat generated by the electrical resistance of the beams heats the tunnel to a predetermined value above the temperature of the air outside of the tunnel. 
     
     
       5. The structure of  claim 2 , wherein at least one of the ceiling, walls, and floor of the tunnel comprises a ferromagnetic shielding material, such as iron, such that magnetic field penetration from within the tunnel to the external environment is minimized. 
     
     
       6. The structure of  claim 1 , wherein the cross sections of the beams of the array are rectangular with rounded corners. 
     
     
       7. The structure of  claim 6 , wherein the rectangular beams are oriented so that the largest dimension (height) of the cross-section of each beam is perpendicular to the single plane. 
     
     
       8. The structure of  claim 6  wherein the corners of each rectangular beam are rounded with radii of curvature equal to ½ of the beam width (smallest dimension of the beam in cross-section) so that the corners of the beam merge to form a half-circle in cross-section at the top and the bottom of the beam. 
     
     
       9. The structure of  claim 8 , wherein the ratio of the radius of curvature of each corner of the rectangular beam to the spacing between beams is chosen to lie between 0.08 and 0.33 such that under normal operating voltages no corona forms anywhere on the beams, and such that upon over-voltage conditions, a corona forms on the rounded top and bottom of the beams at a lower voltage than is necessary to cause either a corona or an arc to form on the flat surfaces of the beams. 
     
     
       10. The structure of  claim 1 , wherein the beams of the array comprise aluminum, the segments for each beam of the array being welded together to form a continuous beam with low electrical resistance and strong mechanical connections between the segments without any overlaps or changes in height or width at the junction between the beam segments. 
     
     
       11. The structure of  claim 1 , wherein when viewed from above along the length of the array, the meander is in the shape of a triangle wave to allow for thermal expansion. 
     
     
       12. The structure of  claim 11 , wherein the right and left meanderings of all the beams in the array are synchronized so that each beam position moves to the right or to the left at the same distance along its length and in the same amount, such that the spacing between each beam and its adjacent beam or beams remains approximately constant throughout its length. 
     
     
       13. The structure of  claim 12 , wherein each insulating structure at each of the periodically spaced locations for each beam comprises two insulating posts mounted such that they form an angle with respect to each other of 30 to 90 degrees. 
     
     
       14. A long-distance, 3-phase, AC electricity transmission structure, comprising: an array of 3N metal active beams for carrying 3-phase AC electricity wherein N is an integer; and a tunnel of rectangular cross-section with either 90 degree or rounded corners, the tunnel comprising two side walls, a ceiling that connects directly to the side walls, and a floor that connects directly to the side walls, the array of beams being mounted within the tunnel and no part of any beam directly contacting the side walls, ceiling or floor; wherein the two side walls of the tunnel are lined with a material having a conductivity similar to the conductivity of the metal of the active beams; wherein at least one of the ceiling or the floor of the tunnel comprises a material that is a poor electrical conductor; wherein the spacing between the adjacent surface of the nearest active beams and either side wall is equal to half the spacing between adjacent surfaces of the active beams in the center of the array; and wherein each beam of the array comprises segments welded together at a slight angle, so that each beam meanders to the right and left when viewed from above along the length of the array, along axes orthogonal to the longitudinal axis of the array. 
     
     
       15. The structure of  claim 14 , additionally comprising:
 an electrically insulating gas or mixture of gases in the space between the beams of the array; and 
 a plurality of insulating structures supporting the beams of the array either from the floor of the tunnel or from the ceiling of the tunnel or both, the insulating structures corresponding to each beam being located at periodically spaced locations along the length of the corresponding beam. 
 
     
     
       16. The structure of  claim 14 , wherein the tunnel is sealed such that the array of beams is protected from weather, such as rain, lightning, fog or snow, and from water incursion. 
     
     
       17. The structure of  claim 16 , wherein the ceiling, the walls, and the floor of the tunnel comprise one or more materials having carefully controlled thermal conductivity, such that the heat generated by the electrical resistance of the beams heats the tunnel to a predetermined value above the temperature of the air outside of the tunnel. 
     
     
       18. The structure of  claim 14 , wherein the cross sections of the beams of the array are rectangular with rounded corners. 
     
     
       19. The structure of  claim 18 , wherein the rectangular beams are oriented so that the largest dimension (height) of the cross-section of each beam is perpendicular to the plane of the tunnel ceiling. 
     
     
       20. The structure of  claim 19 , wherein the corners of each rectangular beam are rounded with radii of curvature equal to ½ of the beam width (smallest dimension of the beam in cross-section) so that the corners of the beam merge to form a half-circle in cross-section at the top and the bottom of the beam. 
     
     
       21. The structure of  claim 20 , wherein the ratio of the radius of curvature of each corner of the rectangular beam to the spacing between beams is chosen to lie between 0.08 and 0.33, such that under normal operating voltages no corona forms anywhere on the beams, and such that upon over-voltage conditions, a corona forms on the rounded top and bottom of the beams at a lower voltage than is necessary to cause either corona or an arc to form on the flat surfaces of the beams. 
     
     
       22. The structure of  claim 14 , wherein the beams of the array comprise aluminum, the segments for each beam of the array being welded together to form a continuous beam with low electrical resistance and strong mechanical connections between the segments without any overlaps or changes in height or width at the junction between the beam segments. 
     
     
       23. The structure of  claim 14 , wherein when viewed from above along the length of the array, the meander is in the shape of a triangle wave. 
     
     
       24. The structure of  claim 23 , wherein the right and left meanderings of all the beams in the array are synchronized so that each beam position moves to the right or to the left at the same distance along its length and in the same amount, such that the spacing between each beam and its adjacent beam or beams remains approximately constant throughout its length. 
     
     
       25. The structure of  claim 24 , wherein each insulating structure at each of the periodically spaced locations for each beam comprises two insulating posts mounted such that they form an angle with respect to each other of 30 to 90 degrees.